[PATCHv4 33/43] ext4: handle huge pages in ext4_page_mkwrite()

[Kirill A. Shutemov]

Trivial: remove assumption on page size.

Signed-off-by: Kirill A. Shutemov <kirill.shute...@linux.intel.com>
---
 fs/ext4/inode.c | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index c36296fbaa23..5ceb72c7bac1 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -5649,7 +5649,7 @@ static int ext4_bh_unmapped(handle_t *handle, struct 
buffer_head *bh)
 
 int ext4_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
 {
-       struct page *page = vmf->page;
+       struct page *page = compound_head(vmf->page);
        loff_t size;
        unsigned long len;
        int ret;
@@ -5685,10 +5685,10 @@ int ext4_page_mkwrite(struct vm_area_struct *vma, 
struct vm_fault *vmf)
                goto out;
        }
 
-       if (page->index == size >> PAGE_SHIFT)
-               len = size & ~PAGE_MASK;
-       else
-               len = PAGE_SIZE;
+       len = hpage_size(page);
+       if (page->index + hpage_nr_pages(page) - 1 == size >> PAGE_SHIFT)
+               len = size & ~hpage_mask(page);
+
        /*
         * Return if we have all the buffers mapped. This avoids the need to do
         * journal_start/journal_stop which can block and take a long time
@@ -5719,7 +5719,8 @@ int ext4_page_mkwrite(struct vm_area_struct *vma, struct 
vm_fault *vmf)
        ret = block_page_mkwrite(vma, vmf, get_block);
        if (!ret && ext4_should_journal_data(inode)) {
                if (ext4_walk_page_buffers(handle, page_buffers(page), 0,
-                         PAGE_SIZE, NULL, do_journal_get_write_access)) {
+                         hpage_size(page), NULL,
+                         do_journal_get_write_access)) {
                        unlock_page(page);
                        ret = VM_FAULT_SIGBUS;
                        ext4_journal_stop(handle);
-- 
2.9.3